Huawei Enables World's First Commercial CSFB Voice Call with LTE TDD Smartphone

Huawei, a leading global information and communications technology (ICT) solutions provider, announced that it enabled the world's first circuit switch fall back (CSFB) voice call between a LTE TDD compatible network and a UMTS network. This CSFB voice call was made through Huawei's STREAM 201HW smartphone, now available through SOFTBANK MOBILE Corp in Japan. To complete the call, the AXGP (Advanced eXtended Global Platform) network was connected with the UMTS network of SOFTBANK MOBILE. AXGP is a network compatible with the LTE TDD of Wireless City Planning Inc., a SoftBank Group company.

CSFB enables the delivery of circuit-switched voice and short message services to LTE devices. When an LTE handset makes or receives a voice call, the device ‘falls back' to a UMTS network to complete the call. This feature is necessary as LTE networks are standard all-IP and packet-based, and do not support circuit-switched calls. Before deploying an IP Multimedia Subsystem (IMS), a 2G/3G network is used to provide voice service for LTE users. Operators can provide voice services for LTE users without deploying IMS for CSFB, but the latter helps operators protect their original investment and provide end-users with voice services and multi-radio access technology (RAT).

Huawei's STREAM 201HW has a customized Qualcomm Integrated Circuit (IC) chip that supports both LTE TDD (AXGP) and UMTS.

Mr. Junichi Miyakawa, Executive Vice President and Chief Technology Officer of SOFTBANK MOBILE, said: "I am so pleased to be making the first CSFB voice call for this occasion. With Huawei's CSFB solution, we can easily protect our investment and provide a seamless experience for data service and voice services."

Mr. Deng Taihua, Huawei President for LTE TDD/WiMAX/TDS Networks, said: "Huawei is honored to provide SOFTBANK MOBILE with this CSFB solution. Interoperation between GSM/UMTS/LTE networks is always a concern for operators. During trials in India August last year, Huawei completed the world's first multiple live handover scenarios across GSM/UMTS/LTE. We are committed to commercializing LTE TDD key solutions for our customers."

Huawei's solutions for commercial LTE TDD deliver the best network performance, the best network convergence and the best end-to-end innovation, to provide the best user experience for customers. To date, Huawei's vision for LTE TDD has helped operators ensure continued business success throughout the Asia-Pacific, Middle East, Europe and Africa.